电牵引采煤机右牵引部齿轮失效分析

Failure Analysis on Right Traction Gear of Electric Traction Shearer

针对牵引减速箱内的齿轮失效问题,通过宏观和微观、断口和磨损面、化学成分分析以及渗碳层的硬度检测,对牵引机构的电机齿轮、惰轮及轴齿轮分别取样进行失效分析。结果表明:这3种齿轮材质均为18Cr2Ni4WA,首先是电机齿轮的失效,从电机齿轮到惰轮、轴齿轮,损坏程度依次减弱。主要原因是电机齿轮的渗碳层深度和硬度不达标,其显微组织中的网状碳化物和残余奥氏体较多,在交变载荷下,裂纹从齿根中心开始萌生,呈放射状向外扩散造成断裂,断裂后,断口再发生严重的磨损。据此,提出了先高温回火,再进行渗碳和淬火的改进措施。

Aiming at the problem of gear failure in traction reducer,the failure analysis of motor gear,idler wheel and shaft gear of traction mechanism was carried out by macroscopic and microscopic analysis,fracture and wear surface,chemical composition analysis and hardness detection of carburized layer.The results show that,the three wheels are made of18 Cr2 Ni4 WA.Firstly the motor gear fails,from motor gear to idler wheel,shaft gear the damage degree is weakened in turn.The main reason is that the carburizing depth and hardness of the motor gear are not up to standard.There are more reticular carbides and retained austenite in the microstructure.Under alternating load,cracks start from the center of the tooth root and spread radially to cause fracture.After fracture,serious wear occurs on the fracture surface.Based on this,the improvement measures of high temperature tempering before carburizing and quenching are put forward.